Fig. 11

a Euclidean distance computed between the virtually cleaned Mona Lisa using the proposed CNN and cleaned reference version, b Euclidean distance computed between the virtually cleaned The Virgin and Child with Saint Anne using the proposed CNN and physically cleaned version, c Euclidean distance computed between the virtually cleaned Mona Lisa using the CNN proposed by [27] and cleaned reference version, d Euclidean distance computed between the virtually cleaned The Virgin and Child with Saint Anne using the CNN proposed by [27] and physically cleaned version, e SA computed between the cleaned reference Mona Lisa using the proposed CNN and physically cleaned version, f SA computed between the virtually cleaned The Virgin and Child with Saint Anne using the proposed CNN and physically cleaned version, g Euclidean distance computed between the virtually cleaned Mona Lisa using the CNN proposed by [27] and cleaned reference version, h Euclidean distance computed between the virtually cleaned The Virgin and Child with Saint Anne using the CNN proposed by [27] and physically cleaned version. Red color shows the largest differences and blue color shows the smallest difference between the cleaned reference and the output images of the proposed method